I am looking for a type of CCD Linear Sensor (2048 pixel, B/W) with a clock-drivers ensure single 5V power supply. Now I found one from SONY ILX554B, but it's a little expensive, do you have some suggestion on a similar one but less expensive?
Chip suggested a barcode scanner, but I don't know of any that are 2K pixels. Even standard fax scanners are less than this; at 200 dpi a 8.5" sensor is 1700 pixels. You're going to need the sensor bar from a large-format fax or page scanner to get the pixel density you need. Surplus is your best bet--maybe even the thrift stores. Sometimes you get lucky and the driver chip is readily hackable. Find the OEM of the sensor, and you can then get datasheets.
As a side note, today's image scanners are often fairly basic -- just a USB interface to a small driver board, connected to the scanner bar and fluorescent light source. One option is to hack this module complete, if you can dig into the software driver. I haven't done this myself, but it might be an option to consider.